title: Enhanced fertility after heat-induced hyperactivation.
abstract: OBJECTIVE
  To determine sperm hyperactivation, kinematic parameters, and fertilizing capacity after pretreating sperm at 40 degrees C for 4 hours.
  
  
  METHODS
  Prospective study involving pooled donor sperm that were colloid washed and incubated at either 23 degrees C (control) or 40 degrees C (heat-treated) for 4 hours as pretreatment. After incubation, analyses were performed with a computer-assisted sperm analyzer, whereas separate portions of sperm were evaluated with the sperm penetration assay at 37 degrees C.
  
  
  METHODS
  Clinical and academic research environment.
  
  
  METHODS
  Cryopreserved-thawed sperm from different donors (n = 5).
  
  
  METHODS
  Sperm kinematic and fertilizing parameters.
  
  
  RESULTS
  Heat pretreatment of sperm resulted in over 22 times higher hyperactive motility at hour 4 compared with the control. The other kinematic parameters were also different. The heat-pretreated sperm group had a significantly higher percent penetration of zona-free oocytes with more swollen sperm heads per oocyte and enhanced sperm binding.
  
  
  CONCLUSIONS
  The results showed that hyperactivation was induced by pretreatment of sperm with 40 degrees C heat, suggesting the involvement of heat factors in hyperactivation. The fertilizing capacity of sperm may be improved by the mild heat pretreatment when marked by the presence of heat-induced hyperactivation.
authors.affiliation: Department of Gynecology and Obstetrics, Loma Linda University School of Medicine, California 92350, USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Chan
authors.forename: J U
authors.initials: JU
authors.lastname: Corselli
authors.forename: W C
authors.initials: WC
authors.lastname: Patton
authors.forename: J D
authors.initials: JD
authors.lastname: Jacobson
authors.forename: A
authors.initials: A
authors.lastname: King
mesh_terms: D005260:Female; D005298:Fertility / Q000502:physiology*; D005306:Fertilization / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012016:Reference Values; D013081:Sperm Motility / Q000502:physiology; D013084:Sperm-Ovum Interactions / Q000502:physiology